Paizo Subscriptions:
Adventure Path: For GMs, this is Paizo's flagship product. One book is released per month, which make up two full campaigns per year. They all begin with 1st-level PCs and wind up somewhere between 12th and 20th level in their final installments.
Modules: Also for GMs, there are fourish a year (if there's any product slippage, it seems like it's always the Module line that gets pushed back). These are shorter campaigns or groups of themed stand-alone adventures. They start and end at various levels.
Campaign Setting: Leaning toward GMs. Flavor and background about the world of Golarion, with some mechanics mixed in. Monthlyish. Used to be called Pathfinder Chronicles.
Player Companion: Geared toward players. Flavor and mechanical options for PCs in Golarion. Also monthlyish. Used to be called Pathfinder Companion.
Pathfinder Roleplaying Game: Hardbacks with mostly world-neutral mechanics and options. Three to four releases per year.
Pathfinder Tales: Novels set in the world of Golarion. Published by Tor. Releases every other month.
Pathfinder Comics: Comics set in the world of Golarion, starring the "iconics." A licensed product published by Dynamite.
Pawns: Heavy cardboard punch-outs with stands, used in place of (or in tandem with) plastic or metal miniatures when playing the game.
Pathfinder Battles: Prepainted plastic miniatures. A licensed product made by WizKids
Pathfinder Adventure Card Game: Card game. Don't know much about it. Class deck subscription also available.
Pathfinder Legends: Audio dramas based on the Adventure Paths and starring the iconics. Also available in digital format.
Pathfinder Cards: Things like item cards, NPC cards, cards for use with chase rules, optional hero-point-style cards.
Pathfinder Maps: Laminated flip maps and packs of connectable map cards.
As far as things being "canonical," except for specified exceptions (i.e., Shattered Star assumes that Rise of the Runelords, Curse of the Crimson Throne, and Second Darkness have occurred in the campaign world), Paizo doesn't advance their timeline in order to keep the products relevant. The assumption is that the events of the APs happen in your world in whichever order your group plays them in. Note that this means that there are very few "world-altering" events in the adventures.
Note that this means that there are very few "world-altering" events in the adventures.
Disagree with this - many of the AP's are world altering (several are world shaking even) - however in general the next AP doesn't assume any of the others have happened. Some have exceptions (such as shattered star) but still run fine if you haven't run the others - running the couple of exceptions can require work to make your timeline 'work' if you are playing in a persistent campaign world, and want to run them out of order.
Here are things that could happen if you play an AP:
I'd call these 'world-altering'.... :)
You forgot one thing
I'll also note that the Adventure Paths have back-matter articles that contain (typically) 4 new Bestiary entries, a serial story (Pathfinder Journal), and 1-2 articles that expand upon the game world in some fashion, such as detailing a god in more detail or giving a gazetteer about a city that was featured in that Adventure Path.
In other words, even if you don't plan on ever running the adventures contained therein, it could be worth picking it up for those articles, if those are the sorts of things that interest you.